This post is an analysis of an early document on Hypertext Design Issues.
The key ideas being discussed in this document are on Hypertext – whether links should be monodirectional or bidirectional, should links be typed etc.
These discussions were conducted in the early days of the web. It is interesting to know how things have evolved since the time this design was made.
Let’s first get some facts right:
Hypertext links today:
- Are Two-ended
- Are Monodirectional
- Have one link
- Are Untyped
- Contain no ancillary information
- Don’t have preview information
What are the implications of this design?
- Hyperlinks are not multiended. A single link cannot link to multiple destinations. There are however cases when one to many, many to one and many to many ‘links’ might make sense. These types of connections among information nodes is what RDF/OWL help achieve.
- an advantage is that often, when a link is made between two nodes, it is made in one direction in the mind of its author, but another reader may be more interested in the reverse link.
Bloggers want to track those pages that have linked to their posts. Google indexes allow us to track links to a particular page. Linkback mechanisms have evolved in the Blogger world to serve precisely this purpose. In general however, we never know who has linked to our page
- It may be useful to have bidirectional links from the point of view of managing data. For example: if a document is destroyed or moved, one is aware of what dangling links will be created, and can possibly fix them.
This problem has not yet been solved. Since links are monodirectional, dangling links cannot be detected. Dangling links – when the information linked to changes, there is no way to clean up the links
- About anchors having one or more links: This is still debatable. There are some utilities that allow you to make every word a hyperlink and allow executing a host of ‘commands’ on the word. Ex: Perform a Google search for the word, lookup the word in dictionary.com, map the word (if it is a city) or lookup in Wikipedia. However I am not a big fan of these utilities since I feel it clutters the screen and the context detection is not yet great.
- Typed links: I feel this is the single most important thing missing from Hyperlinks in WWW. While making types mandatory would have complicated the issue, a standard way to provide ‘types’ to links should have been provided. Anyway, it’s the way it is. So how are people solving this issue? Microformats, RDFa are 2 things I know of. The data is mostly silently read by the browser and tools and users are usually unaware of this data in the pages. In other words, the User Interface for typed links is still not great.
- Meta information associated with links. Interesting! I am aware of Wikipedia articles containing the date when the page was last visited but this is pretty much manually updated as far as I know.
- Preview information: Snap solves this very issue.
Well, it’s tough to say how optimal the design of hypertext on the WWW was. Introducing multi-directional links and typed links would definitely help the technical people out there, but would introduce complexity which would perhaps have made it so tough for the web to flourish that it wouldn’t be what it is today.